The present invention relates to wet/dry steam condensers and, more particularly, to steam condensers which utilize heat pipes having an evaporator section exposed to the steam to-be-condensed and a condensing section cooled by either a cooling air-flow and/or a cooling water-flow.
In the steam power generation cycle, the exhaust steam from the turbine(s) is generally passed through one or more surface-type heat exchanging condensers to remove the heat energy from the steam and effect condensation. A variety of heat exchanging condensers, including the wet-type, the dry-type, and combinations thereof, are known for effecting steam condensation wherein the ultimate heat sink is the atmosphere. In the wet-type, the steam is passed along one side of a heat transfer surface, such as the wall section of a tube, and a heat receiving fluid (e.g. water) is passed along the other side. In the dry-type, air, rather than water, is passed over the heated surface to absorb the heat from the steam. The heated surfaces of the dry-type condenser generally include fins or fin-like structures that increase the heat transfer characteristics and the efficiency of the condenser. In the combined-type of steam condenser, heat energy from the steam may be selectively transferred to the air, and/or water.
Water and air, when used as the heat receiving fluids, each possess certain drawbacks which can hinder the efficient condensation of steam. For example, the quantity of water required by wet-type heat exchangers can be quite large, and, occasionally, water in sufficient quantities and of a minimum acceptable quality may not be available on a consistent year-round basis. Also, the water is heated as it passes through the heat exchanger, and the heated water can cause thermal pollution when it is returned to the environment. Air, while abundantly available, has a low heat capacity, density, and heat transfer rate and requires the use of large, power-consuming fans to create the cooling air flows.
In the past, efforts have been made to increase steam condenser efficiency by fabricating condensers using heat pipes or thermal siphons. These condensers have included a plurality of heat pipes having their lower, evaporator sections exposed to the steam to-be-condensed and their upper, condenser sections exposed to an ambient, cooling air-flow. While heat-pipe steam condensers are effective, their overall heat transfer rates in relation to their capital cost have yet to be optimized.